US20200208577A1 - Ring gear for an epicylic or planetary reduction gear of a turbomachine - Google Patents
Ring gear for an epicylic or planetary reduction gear of a turbomachine Download PDFInfo
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- US20200208577A1 US20200208577A1 US16/623,304 US201816623304A US2020208577A1 US 20200208577 A1 US20200208577 A1 US 20200208577A1 US 201816623304 A US201816623304 A US 201816623304A US 2020208577 A1 US2020208577 A1 US 2020208577A1
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- ring gear
- flanges
- annular
- elements
- gear according
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
- F16H—GEARING
- F16H57/00—General details of gearing
- F16H57/04—Features relating to lubrication or cooling or heating
- F16H57/0467—Elements of gearings to be lubricated, cooled or heated
- F16H57/0479—Gears or bearings on planet carriers
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
- F02C—GAS-TURBINE PLANTS; AIR INTAKES FOR JET-PROPULSION PLANTS; CONTROLLING FUEL SUPPLY IN AIR-BREATHING JET-PROPULSION PLANTS
- F02C7/00—Features, components parts, details or accessories, not provided for in, or of interest apart form groups F02C1/00 - F02C6/00; Air intakes for jet-propulsion plants
- F02C7/36—Power transmission arrangements between the different shafts of the gas turbine plant, or between the gas-turbine plant and the power user
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
- F16H—GEARING
- F16H57/00—General details of gearing
- F16H57/04—Features relating to lubrication or cooling or heating
- F16H57/042—Guidance of lubricant
- F16H57/0421—Guidance of lubricant on or within the casing, e.g. shields or baffles for collecting lubricant, tubes, pipes, grooves, channels or the like
- F16H57/0424—Lubricant guiding means in the wall of or integrated with the casing, e.g. grooves, channels, holes
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
- F16H—GEARING
- F16H57/00—General details of gearing
- F16H57/04—Features relating to lubrication or cooling or heating
- F16H57/042—Guidance of lubricant
- F16H57/043—Guidance of lubricant within rotary parts, e.g. axial channels or radial openings in shafts
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
- F16H—GEARING
- F16H57/00—General details of gearing
- F16H57/04—Features relating to lubrication or cooling or heating
- F16H57/048—Type of gearings to be lubricated, cooled or heated
- F16H57/0482—Gearings with gears having orbital motion
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F05—INDEXING SCHEMES RELATING TO ENGINES OR PUMPS IN VARIOUS SUBCLASSES OF CLASSES F01-F04
- F05D—INDEXING SCHEME FOR ASPECTS RELATING TO NON-POSITIVE-DISPLACEMENT MACHINES OR ENGINES, GAS-TURBINES OR JET-PROPULSION PLANTS
- F05D2250/00—Geometry
- F05D2250/30—Arrangement of components
- F05D2250/31—Arrangement of components according to the direction of their main axis or their axis of rotation
- F05D2250/314—Arrangement of components according to the direction of their main axis or their axis of rotation the axes being inclined in relation to each other
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F05—INDEXING SCHEMES RELATING TO ENGINES OR PUMPS IN VARIOUS SUBCLASSES OF CLASSES F01-F04
- F05D—INDEXING SCHEME FOR ASPECTS RELATING TO NON-POSITIVE-DISPLACEMENT MACHINES OR ENGINES, GAS-TURBINES OR JET-PROPULSION PLANTS
- F05D2260/00—Function
- F05D2260/40—Transmission of power
- F05D2260/403—Transmission of power through the shape of the drive components
- F05D2260/4031—Transmission of power through the shape of the drive components as in toothed gearing
- F05D2260/40311—Transmission of power through the shape of the drive components as in toothed gearing of the epicyclical, planetary or differential type
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F05—INDEXING SCHEMES RELATING TO ENGINES OR PUMPS IN VARIOUS SUBCLASSES OF CLASSES F01-F04
- F05D—INDEXING SCHEME FOR ASPECTS RELATING TO NON-POSITIVE-DISPLACEMENT MACHINES OR ENGINES, GAS-TURBINES OR JET-PROPULSION PLANTS
- F05D2260/00—Function
- F05D2260/98—Lubrication
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
- F16H—GEARING
- F16H57/00—General details of gearing
- F16H57/02—Gearboxes; Mounting gearing therein
- F16H2057/02039—Gearboxes for particular applications
- F16H2057/02043—Gearboxes for particular applications for vehicle transmissions
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
- F16H—GEARING
- F16H57/00—General details of gearing
- F16H57/02—Gearboxes; Mounting gearing therein
- F16H2057/02039—Gearboxes for particular applications
- F16H2057/02069—Gearboxes for particular applications for industrial applications
- F16H2057/02073—Reduction gearboxes for industry
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02T—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION
- Y02T50/00—Aeronautics or air transport
- Y02T50/60—Efficient propulsion technologies, e.g. for aircraft
Definitions
- the field of the present invention is that of turbine engines and more particularly that of differential transmission systems in these turbine engines, in particular planetary or epicyclic reduction gears.
- the prior art comprises in particular documents WO-A1-2010/092263, FR-A1-2 987 416, FR-A1-3 041 730 and FR-A1-3 041 054.
- reduction gears in particular on turbine engines with a fan propeller with a high dilution rate, requires an oil flow rate that is particularly substantial, of about from 6000 to 7000 litres per hour at take-off, in order to ensure the lubrication and the cooling of their pinions and bearings.
- Such a reduction gear comprises a sun pinion or central pinion, an external ring gear and planet pinions which are engaged with the sun pinion and with the ring gear, with the support of one of these three components having to be locked with respect to rotation for the operation of the gear train.
- the central pinion and the ring gear are driving and driven, respectively, or vice versa.
- the reduction gear is then of the type “planetary” type.
- the external ring gear is fixed with respect to rotation and the central pinion and the planet carrier are driving and driven.
- the ring gear extends around the axis of the reduction gear and comprises first and second coaxial annular elements and comprising respectively two inner annular teeth sets of different orientations and intended to cooperate with each planet gear.
- the teeth sets of the ring gear are of the chevron type, with the teeth sets of the elements having propeller angles that are substantially opposite.
- the annular elements of the ring gear respectively comprise first and second radially outer annular flanges for fastening elements together as well as to an annular gear ring carrier intended to extend around at least one portion of the ring gear.
- Document DE-A1-43 04 657 discloses fastening by welding annular elements of a reduction gear ring gear.
- the invention relates here to another technology consisting of bolting the flanges together, i.e. to fasten them together by fastening means of the screw-nut type.
- Centring solutions for a ring gear of this type have already been proposed. However, these solutions are not entirely satisfactory.
- the solution that consists for example of providing a peripheral rim at the inner periphery of the flange of one of the elements, which is intended to be engaged in an annular recess with a shape complementary to the inner periphery of the flange of the other of the elements, is not satisfactory. Indeed, the presence of the rim and of the centring recess in the vicinity of the teeth sets of the elements is liable to hinder the transmission of the forces in the elements and cause different mechanical and vibratory behaviours of the elements during operation, and to result in misalignments of their teeth sets.
- the centring via the interior of the elements prevents bringing the axial position of the webs of these elements closer to the median plane passing between the teeth sets.
- the oil used for the lubrication of the reduction gear during operation must be able to be discharged and, when radial oil passages are provided through the ring gear, they consist in general of radial notches in the centring rim, which are not necessarily regularly distributed around the axis and which can locally increase its flexibility to the detriment of its centring function.
- the invention aims to overcome at least some of the problems and disadvantages mentioned hereinabove.
- the invention relates for this purpose to a ring gear for an epicyclic or planetary reduction gear for a turbine engine, in particular of an aircraft, said ring gear extending around an axis and comprising first and second coaxial annular elements and comprising respectively two inner annular teeth sets of different orientation, said first and second annular elements further comprising respectively first and second radially outer annular flanges for attaching said first and second elements to each other, as well as more preferably to an annular gear ring carrier intended to extend around at least a part of the ring gear via fastening means of the screw-nut type, characterised in that one of said first and second flanges comprises at its outer periphery a cylindrical centring rim configured to cooperate with the outer periphery of the other of said first and second flanges.
- the invention thus proposes to provide the centring of the ring gear elements via the exterior of their flanges, and not via the inside as mentioned hereinabove.
- the cylindrical rim can further be configured to provide centring of the ring gear carrier, by cooperating for example with an outer periphery of an annular fastening flange of this ring gear carrier.
- the ring gear according to the invention can comprise one or more of the following features, taken separately from each other or in combination with each other:
- the present invention also relates to an epicyclic or planetary reduction gear for a turbine engine, in particular of an aircraft, characterised in that it comprises a ring gear such as described hereinabove.
- FIG. 1 schematically shows an axial cross-section of a turbine engine using the invention.
- FIG. 2 shows a detailed cross-section view of an epicyclic reduction gear.
- FIG. 3 is a cutaway perspective view of the reduction gear of FIG. 2 .
- FIG. 4 is a partial axial-section view of a reduction gear provided with a ring gear according to the invention.
- FIG. 5 is a partial perspective view of the ring gear of FIG. 4 .
- FIG. 6 is a partial axial cross-section of the ring gear of FIG. 4 .
- FIG. 1 shows a turbine engine 1 that comprises, conventionally, a fan propeller S, a low-pressure compressor 1 a , a high-pressure compressor 1 b , an annular combustion chamber 1 c , a high-pressure turbine 1 d , a low-pressure turbine 1 e and an exhaust pipe 1 h .
- the high-pressure compressor 1 b and the high-pressure turbine 1 d are connected by a high-pressure shaft 2 and form with it a high-pressure body (HP).
- the low-pressure compressor 1 a and the low-pressure turbine 1 e are connected by a low-pressure shaft 3 and form with it a low-pressure body (LP).
- the fan propeller S is driven by a fan shaft 4 which is coupled to the LP shaft 3 by means of an epicyclic reduction gear 10 shown here schematically.
- the reduction gear 10 is positioned in the front portion of the turbine engine.
- a fixed structure schematically comprising, here, an upstream portion 5 a and a downstream portion 5 b is arranged in such a way as to form an enclosure E 1 that surrounds the reduction gear 10 .
- This enclosure E 1 is here closed upstream by seals on a bearing allowing the fan shaft 4 to pass through, and downstream by seals at the bushing of the LP shaft 3 .
- the reduction gear 10 comprises a ring gear 14 that is fixed via a ring gear carrier (not shown) to the fixed structure 5 a , 5 b with flexible means arranged in order to allow it to follow any movements of the fan shaft 4 , in certain cases with degraded operation for example.
- the ring gear carrier comprises a more or less flexible portion that drives the ring gear and a shafted portion held by roller bearings or bearings and on which the fan is mounted.
- the reduction gear 10 meshes on the one hand on the LP shaft 3 by means of splines 7 which drive a sun gear pinion 11 , and on the other hand on the fan shaft 4 which is attached to a planet carrier 13 .
- the sun pinion 11 the axis of rotation X of which is coincident with that of the turbine engine, drives a series of planet pinions or planet gears 12 , which are regularly distributed over the circumference of the reduction gear 10 .
- the number of planet gears 12 is generally defined between three and six.
- the planet gears 12 also rotate about the axis X of the turbine engine except in the case of a sun gear, where they rotate solely about their axes of revolution, meshing on inner teeth sets of the ring gear 14 , which is fixed to a stator of the turbine engine by means of flanges 20 in the case of an epicyclic gear or fixed to a rotor of the turbine engine in the case of a sun gear.
- Each of the planet gears 12 freely rotates about a planetary shaft 16 connected to the planet carrier 13 , by means of a bearing that can be plain, as shown in FIG. 2 , or a bearing with rolling elements (ball or roller bearings).
- FIG. 2 shows, with FIG. 3 , the movement of the oil to the reduction gear 10 and its movement inside the latter.
- Arrows show in FIG. 2 the path followed by the oil from, in this example, a buffer tank connected to the fixed structure of the turbine engine, to the pinions and to the bearings to be lubricated.
- the lubrication device conventionally comprises three portions: a first portion connected to the fixed structure and delivering the oil to the rotating portions of the reduction gear 10 , an impeller rotating with the planet carrier 13 that receives this oil in the case of an epicyclic gear and of a distributor assembled on the planet carrier, which are fixed on a planetary architecture, and oil distribution circuits supplied with oil by the impeller in order to convey it to the locations to be lubricated.
- FIGS. 4 to 6 show an embodiment of a ring gear 114 according to the invention.
- the ring gear 114 extends around an axis that is the axis X of the reduction gear 110 and of the turbine engine, and comprises two coaxial annular elements, termed first annular element 114 a or upstream element and second annular element 114 b or downstream element.
- Each element 114 a , 114 b comprises an annular body 114 aa , 114 ba of general cylindrical shape and connected to an annular flange 114 ab , 114 bb extending radially outwards.
- Each body 114 aa , 114 ba comprises an inner annular teeth set 150 at its inner periphery.
- the teeth sets 150 of the two bodies or elements are complementary to teeth sets of the planet gears, which are of the type shown in FIG. 3 .
- the teeth sets 150 of the elements 114 a , 114 b are in a chevron.
- Each teeth set 150 comprises an outside diameter that passes through its outer periphery, an inside diameter that passes through its inner periphery, and a pitch diameter D that is measured substantially at mid-height or radial mid-dimension of the teeth set.
- P denotes a median plane of each teeth set, with this plane being substantially perpendicular to the aforementioned axis and passing substantially in the middle of the teeth set in the axial direction.
- the body 114 aa , 114 ba of each element is connected by a longitudinal end to the corresponding flange 114 ab , 114 bb .
- the body 114 aa is connected at its downstream end, located on the side of the other body 114 ba , to the flange 114 ab
- the body 114 ba is connected at its upstream end, located on the side of the other body 114 aa , to the flange 114 bb.
- Each flange 114 ab , 114 bb has the general shape of a dihedron and comprises two peripheral portions, respectively inner 114 ab 1 , 114 bb 1 and outer 114 ab 2 , 114 bb 2 .
- the outer peripheral portions 114 ab 2 , 114 bb 2 extend substantially perpendicularly to the axis and therefore have an orientation that is substantially radial. They are intended to be axially bearing against one another and thus each comprise an annular radial support surface 152 .
- the portions 114 ab 2 , 114 bb 2 are used to fasten the elements 114 a , 114 b together, as well as to a ring gear carrier 154 in the example shown.
- the portions 114 ab 2 , 114 bb 2 each comprise an annular row of axial through-orifices 156 for the passage of the fastening means 158 of the screw-nut or similar type.
- the orifices 156 of the portions 114 ab 2 , 114 bb 2 are aligned and receive the fastening means 158 .
- the ring gear carrier 154 also comprises an annular flange 160 for fastening to the flanges 114 ab , 114 bb and in particular to the portions 114 ab 2 , 114 bb 2 .
- the flange 160 is applied axially to one of the portions 114 ab 2 , 114 bb 2 , namely here the portion 114 ab 2 of the upstream element 114 a .
- the portion 114 ab 2 is thus inserted axially between the flange 160 and the portion 114 bb 2 .
- the converse is also possible. By converse is meant that the ring gear carrier is on the right side of the ring gear, which represents the rear of the engine.
- the flange 160 comprises orifices aligned with the orifices 156 and which also receive the fastening means 158 , heads of which can be axially applied to the downstream face of the portion 114 bb 2 and nuts of which can be axially applied on the upstream face of the flange 160 or vice versa.
- a flange 162 of an annular oil collector is bearing axially on the portion 114 bb 2 and receives on its downstream face the heads of the nuts.
- the portions 114 ab 2 , 114 bb 2 further comprise a first set of axial threaded through-holes 163 that allow for dismantling of the ring gear carrier 154 with the ring gear 114 .
- a second set of axial and tapped through-holes 163 makes it possible to dismantle the element 114 a from the element 114 b .
- the portions 114 ab 2 , 114 bb 2 also comprise at least one pin 165 for the angular fixing of the elements 114 a , 114 b .
- Each portion 114 ab 2 , 114 bb 2 can comprise one or more of these holes 163 , intended to be aligned with one or more similar holes 163 of the other portion, and to receive a fixing pin 165 .
- the pin 165 here has a general cylindrical shape and is oriented axially. It comprises an outer annular bead, substantially at its middle in the axial direction, and intended to be located substantially on surfaces 152 of the flanges.
- the portion 114 bb 2 comprises at its outer periphery a cylindrical centring rim 164 .
- This rim 164 which is carried by the element 114 b , is configured to cooperate by axial sliding and radial support with the outer periphery of the other element 114 a in order to ensure the centring, during mounting and operation, of this other element 114 a .
- the element 114 a could comprise such a rim intended to cooperate with the element 114 b with a view to its centring.
- the rim 164 is intended to cooperate with the outer periphery of the flange 114 ab of the element 114 a , and in particular with the radially external free annular edge of its portion 114 ab 2 . During mounting, the rim 164 thus extends around the portion 114 ab 2 .
- the rim 164 also ensures the centring of the ring gear carrier 154 .
- the rim 164 can cooperate as indicated hereinabove with the outer periphery of the flange 160 .
- the rim 164 extends here continuously over 360°. It is thus neither split nor sectorised. The reference surface for the centring is thus uninterrupted.
- the inner peripheral portions 114 ab 1 , 114 bb 1 are angled with respect to the axis X of the ring gear 114 .
- the portion 114 ab 1 extends radially from upstream to downstream in the direction outwards, and the portion 114 bb 1 extends from upstream to downstream in the direction inwards.
- the portions 114 ab 1 , 114 bb 1 are angled from 0° to 90° with respect to the axis of rotation of the ring gear X and more preferably between 30 and 60° and delimit an annular cavity 166 with a cross-section of generally triangular shape, the tip of which is oriented radially outwards.
- Their axial positions are such that the neutral fibre passes through the intersection of the median plane of the teeth set as well as its pitch diameter.
- the portions 114 ab 1 , 114 bb 1 make it possible to connect the portions 114 ab 2 , 114 bb 2 to the bodies of the elements 114 aa , 114 bb . Due to the orientation of the portions 114 ab 1 , 114 bb 1 and their connection to the longitudinal ends, respectively downstream and upstream, of the bodies 114 a , 114 b these bodies are axially separated from each other by a predetermined distance.
- Lubrication oil is intended to flow during operation through this inter-body space and penetrate into the cavity 166 .
- Substantially radial passages are provided between the flanges 114 ab , 114 bb in order to allow for the removal of the oil radially towards the exterior of the ring gear.
- the oil passages are here formed on the one hand by substantially radial notches 168 or slots formed in the surfaces 152 of the flanges.
- Each flange comprises an annular row of notches 168 that are axially aligned with notches 168 on the other of the flanges.
- the notches are produced at a distance from the orifices 156 for passage of the fastening means 158 , from the hole of the pin 165 and from the holes 163 .
- Each notch has for example a cross-section of semicircular (half-oblong) or rectangular shape as in the example shown ( FIG. 5 ).
- the notches are in fluidic communication, at their radially internal ends, with the cavity 166 , and at their axially external ends with oblong-shaped oil outlet through-orifices 170 formed in the centring rim 164 .
- the oil passages open at their radially external ends onto the outer cylindrical surface of the rim 164 , to form there oil outlet orifices 170 .
- FIG. 6 shows a partial axial cross-section of the reduction gear 110 in which Y designates the intersection between the plane P and the pitch diameter D for each teeth set 150 .
- the inner peripheral portion 114 ab 1 , 114 bb 1 of each flange extends in a plane that passes substantially through the intersection point Y. This position as well as the aforementioned inclination are two important parameters in this embodiment.
- Each inner peripheral portion 114 ab 1 , 114 bb 1 has an inner peripheral surface 115 a that extends radially outwards in the extension of an end radial surface 115 b of the corresponding body.
- the axial distance between the surfaces 115 b corresponds to the inter-element distance and to the maximum axial dimension of the cavity 166 .
- the inner peripheral portions 114 ab 1 , 114 bb 1 have a substantially constant thickness.
- the ring gear elements 114 a , 114 b are symmetrical with respect to a median plane, perpendicular to the axis and passing substantially between the elements.
- the ring gear 114 according to the invention is easier to produce, mount and control than those of prior technologies.
- the invention can be applied to an epicyclic or planetary architecture.
- the ring gear In the first, the ring gear is fixed and in the second the ring gear rotates around the engine shaft.
- the epicyclic or planetary ring gear are held by the ring gear carrier.
- the ring gear carrier can have a shape, a movement and a function that is different according to the type of architecture.
- the fan shaft portion In the case of an epicyclic architecture, the fan shaft portion is on the planet carrier and in the case of a planetary architecture it is located on the ring gear carrier.
Abstract
Description
- The field of the present invention is that of turbine engines and more particularly that of differential transmission systems in these turbine engines, in particular planetary or epicyclic reduction gears.
- The prior art comprises in particular documents WO-A1-2010/092263, FR-A1-2 987 416, FR-A1-3 041 730 and FR-A1-3 041 054.
- Current turbine engines, in particular turbine engines that comprise one or more fan propellers for a secondary flow, comprise a transmission system, called a reduction gear, to drive this or these propellers at the correct rotation speed using the power turbine shaft of the primary body of the engine.
- The operation of reduction gears, in particular on turbine engines with a fan propeller with a high dilution rate, requires an oil flow rate that is particularly substantial, of about from 6000 to 7000 litres per hour at take-off, in order to ensure the lubrication and the cooling of their pinions and bearings.
- Among the reduction gears used, there are planetary and epicyclical (with train) reduction gears which have the advantage of offering substantial reduction rates in the rotation speed in reduced spaces.
- Such a reduction gear comprises a sun pinion or central pinion, an external ring gear and planet pinions which are engaged with the sun pinion and with the ring gear, with the support of one of these three components having to be locked with respect to rotation for the operation of the gear train.
- When the planet carrier is fixed with respect to rotation, the central pinion and the ring gear are driving and driven, respectively, or vice versa. The reduction gear is then of the type “planetary” type.
- In the opposite case, of an epicyclical reduction gear, the external ring gear is fixed with respect to rotation and the central pinion and the planet carrier are driving and driven.
- The main problem with this type of reduction gear is ensuring optimum meshing of each planet gear on the one hand with the central pinion but also with the ring gear.
- The ring gear extends around the axis of the reduction gear and comprises first and second coaxial annular elements and comprising respectively two inner annular teeth sets of different orientations and intended to cooperate with each planet gear. The teeth sets of the ring gear are of the chevron type, with the teeth sets of the elements having propeller angles that are substantially opposite.
- The annular elements of the ring gear respectively comprise first and second radially outer annular flanges for fastening elements together as well as to an annular gear ring carrier intended to extend around at least one portion of the ring gear.
- Document DE-A1-43 04 657 discloses fastening by welding annular elements of a reduction gear ring gear. The invention relates here to another technology consisting of bolting the flanges together, i.e. to fasten them together by fastening means of the screw-nut type.
- In the prior art, either for an epicyclic or planetary architecture, it is difficult to ensure optimum centring of the elements, as well as of the ring gear carrier. This centring or axial alignment is important in order to minimise any misalignment of the teeth sets of the ring gear elements during operation. The geometry of the aforementioned flanges directly influences the misalignment of the teeth sets during operation. The elements tend to come closer or to separate according to the vibration modes and the shapes of the teeth sets, the forces which are transmitted to the ring gear carrier by the flanges of the ring gear. In addition, a precise angular adjustment is necessary between the two elements in order to angularly locate the teeth sets of the elements.
- Centring solutions for a ring gear of this type have already been proposed. However, these solutions are not entirely satisfactory. The solution that consists for example of providing a peripheral rim at the inner periphery of the flange of one of the elements, which is intended to be engaged in an annular recess with a shape complementary to the inner periphery of the flange of the other of the elements, is not satisfactory. Indeed, the presence of the rim and of the centring recess in the vicinity of the teeth sets of the elements is liable to hinder the transmission of the forces in the elements and cause different mechanical and vibratory behaviours of the elements during operation, and to result in misalignments of their teeth sets. Secondly, the centring via the interior of the elements prevents bringing the axial position of the webs of these elements closer to the median plane passing between the teeth sets. Moreover, the oil used for the lubrication of the reduction gear during operation must be able to be discharged and, when radial oil passages are provided through the ring gear, they consist in general of radial notches in the centring rim, which are not necessarily regularly distributed around the axis and which can locally increase its flexibility to the detriment of its centring function.
- The invention aims to overcome at least some of the problems and disadvantages mentioned hereinabove.
- The invention relates for this purpose to a ring gear for an epicyclic or planetary reduction gear for a turbine engine, in particular of an aircraft, said ring gear extending around an axis and comprising first and second coaxial annular elements and comprising respectively two inner annular teeth sets of different orientation, said first and second annular elements further comprising respectively first and second radially outer annular flanges for attaching said first and second elements to each other, as well as more preferably to an annular gear ring carrier intended to extend around at least a part of the ring gear via fastening means of the screw-nut type, characterised in that one of said first and second flanges comprises at its outer periphery a cylindrical centring rim configured to cooperate with the outer periphery of the other of said first and second flanges.
- The invention thus proposes to provide the centring of the ring gear elements via the exterior of their flanges, and not via the inside as mentioned hereinabove. The cylindrical rim can further be configured to provide centring of the ring gear carrier, by cooperating for example with an outer periphery of an annular fastening flange of this ring gear carrier.
- The ring gear according to the invention can comprise one or more of the following features, taken separately from each other or in combination with each other:
-
- said cylindrical rim extends continuously over 360°; this allows for a better distribution of the stresses after a shrunk-on assembly for example,
- each of said first and second flanges comprises an outer peripheral portion extending in a plane that is substantially perpendicular to said axis, and an inner peripheral portion extending in a plane that is angled with respect to said axis; this allows for the centring of the annular elements and indirectly the out-of-roundness of the teeth sets of each element; the precision of this centring has a significant impact on misalignment;
- said peripheral rim is located at the outer periphery of said outer peripheral portion of one of said first and second flanges; this makes it possible to release space on the inner periphery in order to create symmetrical flanges, and to bring them axially closer to each other;
- said rim allows for the assembly of the annular elements together and the assembly of the ring gear with the ring gear carrier;
- said outer peripheral portions of said first and second flanges are axially bearing against one another and comprise axial through-orifices for the passage of said fastening means; this makes it possible to transmit the torque between each annular element and the ring gear carrier;
- comprise radial bearing surfaces in which are formed radial notches (or slots) for the passage of oil; this makes it possible to create an oil passage and to lighten the parts;
- said radial notches (or slots) communicate at their radially external ends with radial through-orifices formed in said cylindrical rim; this allows the oil to escape via the outside of the centring of the annular elements;
- said radial notches (or slots) communicate at their radially internal ends with an internal annular cavity with a substantially triangular section and formed by said inner peripheral portions of said first and second flanges; machining tapping can be used in the present case in order to have a larger radius, which has the effect of reducing the stresses in this zone, which is relatively loaded; it also makes it possible to achieve the centring and the axial bearing face in a different operation with different parameters;
- said outer peripheral portions of said first and second flanges comprise axial through-holes for mounting at least one pin for the angular adjustment of said first and second elements; this allows the orientation of the two annular elements in order to create a correct orientation of the teeth sets. The orientation has a direct influence on the position of the APEX of the teeth sets.
- The present invention also relates to an epicyclic or planetary reduction gear for a turbine engine, in particular of an aircraft, characterised in that it comprises a ring gear such as described hereinabove.
- The present invention will be better understood and other details, features and advantages of the present invention will appear more clearly when reading the following description, in reference to the accompanying drawings in which:
-
FIG. 1 schematically shows an axial cross-section of a turbine engine using the invention. -
FIG. 2 shows a detailed cross-section view of an epicyclic reduction gear. -
FIG. 3 is a cutaway perspective view of the reduction gear ofFIG. 2 . -
FIG. 4 is a partial axial-section view of a reduction gear provided with a ring gear according to the invention. -
FIG. 5 is a partial perspective view of the ring gear ofFIG. 4 . -
FIG. 6 is a partial axial cross-section of the ring gear ofFIG. 4 . -
FIG. 1 shows aturbine engine 1 that comprises, conventionally, a fan propeller S, a low-pressure compressor 1 a, a high-pressure compressor 1 b, an annular combustion chamber 1 c, a high-pressure turbine 1 d, a low-pressure turbine 1 e and an exhaust pipe 1 h. The high-pressure compressor 1 b and the high-pressure turbine 1 d are connected by a high-pressure shaft 2 and form with it a high-pressure body (HP). The low-pressure compressor 1 a and the low-pressure turbine 1 e are connected by a low-pressure shaft 3 and form with it a low-pressure body (LP). - The fan propeller S is driven by a fan shaft 4 which is coupled to the LP shaft 3 by means of an
epicyclic reduction gear 10 shown here schematically. - The
reduction gear 10 is positioned in the front portion of the turbine engine. A fixed structure schematically comprising, here, anupstream portion 5 a and adownstream portion 5 b is arranged in such a way as to form an enclosure E1 that surrounds thereduction gear 10. This enclosure E1 is here closed upstream by seals on a bearing allowing the fan shaft 4 to pass through, and downstream by seals at the bushing of the LP shaft 3. - In reference to
FIGS. 2 and 3 , thereduction gear 10 comprises a ring gear 14 that is fixed via a ring gear carrier (not shown) to thefixed structure - The
reduction gear 10 meshes on the one hand on the LP shaft 3 by means of splines 7 which drive asun gear pinion 11, and on the other hand on the fan shaft 4 which is attached to aplanet carrier 13. Conventionally, thesun pinion 11, the axis of rotation X of which is coincident with that of the turbine engine, drives a series of planet pinions or planet gears 12, which are regularly distributed over the circumference of thereduction gear 10. The number of planet gears 12 is generally defined between three and six. The planet gears 12 also rotate about the axis X of the turbine engine except in the case of a sun gear, where they rotate solely about their axes of revolution, meshing on inner teeth sets of the ring gear 14, which is fixed to a stator of the turbine engine by means offlanges 20 in the case of an epicyclic gear or fixed to a rotor of the turbine engine in the case of a sun gear. Each of the planet gears 12 freely rotates about aplanetary shaft 16 connected to theplanet carrier 13, by means of a bearing that can be plain, as shown inFIG. 2 , or a bearing with rolling elements (ball or roller bearings). - The rotation of the planet gears 12 about their
planetary axis 16, due to the cooperation of their pinions with the teeth sets of the ring gear 14, causes the rotation of theplanet carrier 13 about the axis X, and consequently that of the fan shaft 4 that is connected to it, at a rotation speed that is less than that of the LP shaft 3. -
FIG. 2 shows, withFIG. 3 , the movement of the oil to thereduction gear 10 and its movement inside the latter. Arrows show inFIG. 2 the path followed by the oil from, in this example, a buffer tank connected to the fixed structure of the turbine engine, to the pinions and to the bearings to be lubricated. The lubrication device conventionally comprises three portions: a first portion connected to the fixed structure and delivering the oil to the rotating portions of thereduction gear 10, an impeller rotating with theplanet carrier 13 that receives this oil in the case of an epicyclic gear and of a distributor assembled on the planet carrier, which are fixed on a planetary architecture, and oil distribution circuits supplied with oil by the impeller in order to convey it to the locations to be lubricated. -
FIGS. 4 to 6 show an embodiment of aring gear 114 according to the invention. - The
ring gear 114 extends around an axis that is the axis X of thereduction gear 110 and of the turbine engine, and comprises two coaxial annular elements, termed firstannular element 114 a or upstream element and second annular element 114 b or downstream element. - Each
element 114 a, 114 b comprises anannular body 114 aa, 114 ba of general cylindrical shape and connected to anannular flange 114 ab, 114 bb extending radially outwards. - Each
body 114 aa, 114 ba comprises an inner annular teeth set 150 at its inner periphery. Although not visible in the drawings, the teeth sets 150 of the two bodies or elements are complementary to teeth sets of the planet gears, which are of the type shown inFIG. 3 . The teeth sets 150 of theelements 114 a, 114 b are in a chevron. - Each teeth set 150 comprises an outside diameter that passes through its outer periphery, an inside diameter that passes through its inner periphery, and a pitch diameter D that is measured substantially at mid-height or radial mid-dimension of the teeth set. Moreover, P denotes a median plane of each teeth set, with this plane being substantially perpendicular to the aforementioned axis and passing substantially in the middle of the teeth set in the axial direction.
- The
body 114 aa, 114 ba of each element is connected by a longitudinal end to thecorresponding flange 114 ab, 114 bb. Thebody 114 aa is connected at its downstream end, located on the side of theother body 114 ba, to theflange 114 ab, and thebody 114 ba is connected at its upstream end, located on the side of theother body 114 aa, to theflange 114 bb. - Each
flange 114 ab, 114 bb has the general shape of a dihedron and comprises two peripheral portions, respectively inner 114ab bb 1 and outer 114ab 2, 114 bb 2. - The outer
peripheral portions 114ab 2, 114 bb 2 extend substantially perpendicularly to the axis and therefore have an orientation that is substantially radial. They are intended to be axially bearing against one another and thus each comprise an annularradial support surface 152. - The
portions 114ab 2, 114 bb 2 are used to fasten theelements 114 a, 114 b together, as well as to aring gear carrier 154 in the example shown. - For this, the
portions 114ab 2, 114 bb 2 each comprise an annular row of axial through-orifices 156 for the passage of the fastening means 158 of the screw-nut or similar type. Theorifices 156 of theportions 114ab 2, 114 bb 2 are aligned and receive the fastening means 158. - The
ring gear carrier 154 also comprises anannular flange 160 for fastening to theflanges 114 ab, 114 bb and in particular to theportions 114ab 2, 114 bb 2. Theflange 160 is applied axially to one of theportions 114ab 2, 114 bb 2, namely here theportion 114 ab 2 of theupstream element 114 a. Theportion 114 ab 2 is thus inserted axially between theflange 160 and theportion 114 bb 2. The converse is also possible. By converse is meant that the ring gear carrier is on the right side of the ring gear, which represents the rear of the engine. - The
flange 160 comprises orifices aligned with theorifices 156 and which also receive the fastening means 158, heads of which can be axially applied to the downstream face of theportion 114 bb 2 and nuts of which can be axially applied on the upstream face of theflange 160 or vice versa. In the example shown, aflange 162 of an annular oil collector is bearing axially on theportion 114 bb 2 and receives on its downstream face the heads of the nuts. - The
portions 114ab 2, 114 bb 2 further comprise a first set of axial threaded through-holes 163 that allow for dismantling of thering gear carrier 154 with thering gear 114. A second set of axial and tapped through-holes 163 makes it possible to dismantle theelement 114 a from the element 114 b. Theportions 114ab 2, 114 bb 2 also comprise at least onepin 165 for the angular fixing of theelements 114 a, 114 b. Eachportion 114ab 2, 114 bb 2 can comprise one or more of these holes 163, intended to be aligned with one or more similar holes 163 of the other portion, and to receive a fixingpin 165. Thepin 165 here has a general cylindrical shape and is oriented axially. It comprises an outer annular bead, substantially at its middle in the axial direction, and intended to be located substantially onsurfaces 152 of the flanges. - The
portion 114 bb 2 comprises at its outer periphery acylindrical centring rim 164. Thisrim 164, which is carried by the element 114 b, is configured to cooperate by axial sliding and radial support with the outer periphery of theother element 114 a in order to ensure the centring, during mounting and operation, of thisother element 114 a. Alternatively, theelement 114 a could comprise such a rim intended to cooperate with the element 114 b with a view to its centring. - The
rim 164 is intended to cooperate with the outer periphery of theflange 114 ab of theelement 114 a, and in particular with the radially external free annular edge of itsportion 114 ab 2. During mounting, therim 164 thus extends around theportion 114 ab 2. - In the example shown, the
rim 164 also ensures the centring of thering gear carrier 154. Therim 164 can cooperate as indicated hereinabove with the outer periphery of theflange 160. - The
rim 164 extends here continuously over 360°. It is thus neither split nor sectorised. The reference surface for the centring is thus uninterrupted. - The inner
peripheral portions 114ab bb 1 are angled with respect to the axis X of thering gear 114. Theportion 114ab 1 extends radially from upstream to downstream in the direction outwards, and theportion 114bb 1 extends from upstream to downstream in the direction inwards. In the example shown, theportions 114ab bb 1 are angled from 0° to 90° with respect to the axis of rotation of the ring gear X and more preferably between 30 and 60° and delimit an annular cavity 166 with a cross-section of generally triangular shape, the tip of which is oriented radially outwards. Their axial positions are such that the neutral fibre passes through the intersection of the median plane of the teeth set as well as its pitch diameter. - The
portions 114ab bb 1 make it possible to connect theportions 114ab 2, 114 bb 2 to the bodies of theelements 114 aa, 114 bb. Due to the orientation of theportions 114ab bb 1 and their connection to the longitudinal ends, respectively downstream and upstream, of thebodies 114 a, 114 b these bodies are axially separated from each other by a predetermined distance. - Lubrication oil is intended to flow during operation through this inter-body space and penetrate into the cavity 166. Substantially radial passages are provided between the
flanges 114 ab, 114 bb in order to allow for the removal of the oil radially towards the exterior of the ring gear. - The oil passages are here formed on the one hand by substantially
radial notches 168 or slots formed in thesurfaces 152 of the flanges. Each flange comprises an annular row ofnotches 168 that are axially aligned withnotches 168 on the other of the flanges. The notches are produced at a distance from theorifices 156 for passage of the fastening means 158, from the hole of thepin 165 and from the holes 163. Each notch has for example a cross-section of semicircular (half-oblong) or rectangular shape as in the example shown (FIG. 5 ). - The notches are in fluidic communication, at their radially internal ends, with the cavity 166, and at their axially external ends with oblong-shaped oil outlet through-
orifices 170 formed in thecentring rim 164. In other words, the oil passages open at their radially external ends onto the outer cylindrical surface of therim 164, to form thereoil outlet orifices 170. -
FIG. 6 shows a partial axial cross-section of thereduction gear 110 in which Y designates the intersection between the plane P and the pitch diameter D for each teeth set 150. As can be seen in the drawing, the innerperipheral portion 114ab bb 1 of each flange extends in a plane that passes substantially through the intersection point Y. This position as well as the aforementioned inclination are two important parameters in this embodiment. - Each inner
peripheral portion 114ab bb 1 has an innerperipheral surface 115 a that extends radially outwards in the extension of an endradial surface 115 b of the corresponding body. The axial distance between thesurfaces 115 b corresponds to the inter-element distance and to the maximum axial dimension of the cavity 166. - The inner
peripheral portions 114ab bb 1 have a substantially constant thickness. - Except for the
rim 164, thering gear elements 114 a, 114 b are symmetrical with respect to a median plane, perpendicular to the axis and passing substantially between the elements. - The
ring gear 114 according to the invention is easier to produce, mount and control than those of prior technologies. - The invention can be applied to an epicyclic or planetary architecture. In the first, the ring gear is fixed and in the second the ring gear rotates around the engine shaft. The epicyclic or planetary ring gear are held by the ring gear carrier. However, the ring gear carrier can have a shape, a movement and a function that is different according to the type of architecture. In the case of an epicyclic architecture, the fan shaft portion is on the planet carrier and in the case of a planetary architecture it is located on the ring gear carrier.
Claims (10)
Applications Claiming Priority (3)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
FR1756346A FR3068750B1 (en) | 2017-07-05 | 2017-07-05 | EPICYCLOIDAL OR PLANETARY REDUCER CROWN FOR A TURBOMACHINE |
FR1756346 | 2017-07-05 | ||
PCT/EP2018/066963 WO2019007742A1 (en) | 2017-07-05 | 2018-06-25 | Ring gear for an epicyclic or planetary reduction gear of a turbomachine |
Publications (2)
Publication Number | Publication Date |
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US20200208577A1 true US20200208577A1 (en) | 2020-07-02 |
US11326524B2 US11326524B2 (en) | 2022-05-10 |
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US16/623,304 Active 2038-10-31 US11326524B2 (en) | 2017-07-05 | 2018-06-25 | Ring gear for an epicyclic or planetary reduction gear of a turbomachine |
Country Status (5)
Country | Link |
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US (1) | US11326524B2 (en) |
EP (1) | EP3649378B1 (en) |
CN (1) | CN110770476B (en) |
FR (1) | FR3068750B1 (en) |
WO (1) | WO2019007742A1 (en) |
Cited By (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
FR3119431A1 (en) * | 2021-02-03 | 2022-08-05 | Safran Transmission Systems | Mechanical reducer |
US11708794B2 (en) | 2020-08-04 | 2023-07-25 | Ge Avio S.R.L. | Gearbox efficiency rating for turbomachine engines |
US11713721B1 (en) | 2022-01-31 | 2023-08-01 | Ge Avio S.R.L. | Overall engine efficiency rating for turbomachine engines |
Families Citing this family (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
FR3093550B1 (en) * | 2019-03-07 | 2021-02-19 | Safran Aircraft Engines | AIRCRAFT TURBOMACHINE MECHANICAL REDUCER |
FR3098562B1 (en) * | 2019-07-08 | 2021-06-11 | Safran Trans Systems | OIL LINE COVER AND MECHANICAL REDUCER OF AIRCRAFT TURBOMACHINE WITH SUCH COVER |
Family Cites Families (11)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
DE4304657A1 (en) * | 1992-05-18 | 1993-11-25 | Zahnradfabrik Friedrichshafen | Double-helical epicyclic gear train - has annulus in halves with opposite-inclined teeth and positively joined together |
JP3391146B2 (en) * | 1995-05-18 | 2003-03-31 | 株式会社デンソー | Starter |
US8167727B2 (en) * | 2009-10-02 | 2012-05-01 | Opra Technologies | High speed gear coupler |
US8708863B2 (en) * | 2006-08-15 | 2014-04-29 | United Technologies Corporation | Epicyclic gear train |
FR2908452A1 (en) * | 2006-11-15 | 2008-05-16 | Snecma Sa | Fastener device for a gas turbine engine has a flange that provides releasable connections by mutual engagement between turbine stator and a gas generator casing and a sliding joint that provides centering of turbine stator on the casing |
FR2942284B1 (en) | 2009-02-16 | 2011-03-04 | Snecma | LUBRICATION AND COOLING OF AN EPICYCLOIDAL GEAR TRAIN REDUCER |
JP4785976B1 (en) * | 2010-04-13 | 2011-10-05 | 川崎重工業株式会社 | Planetary gear set |
JP5750014B2 (en) * | 2011-09-19 | 2015-07-15 | アイシン・エィ・ダブリュ株式会社 | Planetary gear unit |
FR2987416B1 (en) | 2012-02-23 | 2015-09-04 | Snecma | DEVICE FOR LUBRICATING AN EPICYCLOIDAL REDUCER. |
FR3041054B1 (en) | 2015-09-15 | 2017-09-15 | Hispano-Suiza | OIL SUPPLY DEVICE FOR AN EPICYCLOIDAL TRAIN REDUCER. |
FR3041730B1 (en) * | 2015-09-30 | 2018-12-07 | Safran Transmission Systems | DEVICE FOR MOUNTING A CROWN OF AN EPICYCLOIDAL TRAIN |
-
2017
- 2017-07-05 FR FR1756346A patent/FR3068750B1/en not_active Expired - Fee Related
-
2018
- 2018-06-25 US US16/623,304 patent/US11326524B2/en active Active
- 2018-06-25 EP EP18737516.7A patent/EP3649378B1/en active Active
- 2018-06-25 WO PCT/EP2018/066963 patent/WO2019007742A1/en unknown
- 2018-06-25 CN CN201880040238.3A patent/CN110770476B/en active Active
Cited By (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US11708794B2 (en) | 2020-08-04 | 2023-07-25 | Ge Avio S.R.L. | Gearbox efficiency rating for turbomachine engines |
FR3119431A1 (en) * | 2021-02-03 | 2022-08-05 | Safran Transmission Systems | Mechanical reducer |
EP4040019A1 (en) * | 2021-02-03 | 2022-08-10 | Safran Transmission Systems | Mechanical reduction gear |
US11808213B2 (en) | 2021-02-03 | 2023-11-07 | Safran Transmission Systems | Mechanical reducer |
US11713721B1 (en) | 2022-01-31 | 2023-08-01 | Ge Avio S.R.L. | Overall engine efficiency rating for turbomachine engines |
Also Published As
Publication number | Publication date |
---|---|
WO2019007742A1 (en) | 2019-01-10 |
US11326524B2 (en) | 2022-05-10 |
FR3068750A1 (en) | 2019-01-11 |
CN110770476A (en) | 2020-02-07 |
CN110770476B (en) | 2023-03-14 |
EP3649378A1 (en) | 2020-05-13 |
FR3068750B1 (en) | 2020-02-07 |
EP3649378B1 (en) | 2021-08-04 |
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